This invention relates to agricultural balers for forming round bales of crop material and automatically wrapping the bales with twine before releasing them onto a field. More particularly, the invention relates to improvements in the twine wrapper control system to (1) improve the chances that the end of the twine will be caught up in a rotating bale at the start of a wrapping cycle and (2) provide for automatic restarting of a wrapping cycle in the event the twine is not caught up.
Typical automatic round balers, such as the models 544 and 5930 commercially available from New Holland North America, pick up crop material from a field and form it into a compacted round bale in a bale-forming chamber. When the bale has been compacted to a desired density (or reached a desired size), bale density (or size) sensors send signals to a controller which in turn sends a signal to an operator""s panel to signal the operator to stop forward motion of the baler so that the bale may be wrapped with netting or twine according to a program of instructions stored in a controller memory.
After a brief delay allowing time for the operator to stop forward motion of the baler, the controller initiates a wrap cycle. The mechanism for wrapping with twine includes two hollow twine tubes. Two strands of twine are fed from two twine rolls through the tubes. When a wrap cycle is initiated, the twine tubes are moved arcuately to an extended or insert position with an end of one strand dangling from the end of a respective one of the tubes. A pusher mechanism, usually referred to as a xe2x80x9cduckbillxe2x80x9d, is actuated to move the dangling ends toward the bale so that the ends of the twine strands are adjacent the bale near its lengthwise middle. The strands are caught up in the bale that is rotating within the bale-forming chamber. The bale is then wrapped in a pattern by moving the twine tubes toward a home position with programmed pauses at intervals to place circular wraps on the bale. The twine is cut after end wraps have been placed on the bale.
As the twine tubes move toward their home positions, each twine strand slides into a spring clamp and hold device so that the twine ends can not be caught up in moving machine parts after the strands are cut. The strands are then cut. Each strand is pulled out of its respective clamp and hold device at the beginning of the next wrap cycle as the twine tube arms are extended to the insert position.
It has been found that a frequent cause of failure in wrapping is due to the fact that the end of a strand does not drop quickly enough after being pulled free of its clamping device. As a result, the strand end drops onto the top of the duckbill rather than dangling in a position where it can be pushed toward the bale by the duckbill.
Hence there is a need for a system wherein the chance of failures in inserting the ends of the twine strands is considerably reduced.
A stored program in the controller determines the pattern in which the bale is wrapped. This program may be a factory-installed program, a xe2x80x9clearnedxe2x80x9d program generated by manually controlling movement of the twine tubes to place the desired wrap pattern on a bale, or a factory-installed program which permits operator selection of the number of end wraps to be placed on a bale. In any event, the programs provide no easy method for restarting a twine wrap cycle to re-tie a bale in the event one or both strand ends are not caught up in the rotating bale.
Typically, the operator may wait until the selected twine pattern program completes its automatic wrap cycle and then restart the wrap cycle by actuating, for two seconds, a Wrap key on an operator""s control panel. This procedure wastes a considerable amount of twine if one strand was caught up in the rotating bale. Alternatively, the operator may manually return the twine tubes to their home position by (1) actuating a Retract key on the operator""s control panel to retract the twine tubes to their home position, (2) switching the controller to the net wrap mode by actuating a Net/Twine key, (3) again actuating the Retract key to return the duckbill to its home position and cut the twine, (4) actuating a Clear key to clear the error alarm and error message displayed on the operator""s control panel (caused by interruption of the wrap cycle), (5) actuating the Net/Twine key to return the controller to the twine wrap mode, and (6) initiating a new wrap cycle by actuating the Wrap key for two seconds. This complex procedure requires a very skilled and knowledgeable operator and wastes considerable time. It also wastes twine if one strand is started but, as compared to the first procedure, results in less waste.
In copending application Ser. No. 09/362,723 the problems described above are solved by providing a control system for controlling the wrapping of bales of crop material, the control system being characterized in that, in the event of a malfunction during a wrapping cycle the twine is cut, the system restored to an initial state and a new wrapping cycle initiated by actuating a Wrap key on an operator""s control panel.
An object of the present invention is to provide a round baler wherein, upon a failure in inserting an end of one of the wrapping twine strands, a new wrapping cycle may be initiated without the need for the operator to actuate the Wrap key. Provision is made for a limited number of attempts to insert the strands. If the strands are not properly inserted after a limited number of attempts, say three, an alarm is sounded and a wrapping fault message is displayed on an operator""s control panel. In this case the operator may turn the power off, inspect the wrapping mechanism and, if need be, repair it, turn the power back on, and press a wrap key to initiate a new series of attempt to wrap the bale.
Another object of the invention is to provide a round baler wherein the twine tubes are moved to their twine insert positions prior to the time a full bale is formed, and an alarm is sounded and a bale wrap cycle automatically initiated when the bale reaches a preset size. The alarm signals the operator to stop forward motion of the baler. It is not necessary for the operator to press the wrap key in order to initiate the wrap cycle.
A further object of the invention is to provide a bale wrapping system for wrapping a rotating bale of crop material with at least one strand of twine, the bale wrapping system comprising: at least one twine dispensing arm for presenting at least one strand of twine so that an end of the strand may dangle from the arm, the arm being movable between a home position and a twine insert position where the end of the strand dangles adjacent the rotating bale; a twine pusher movable between a first position at which it cuts the strand and a second position at which it pushes the dangling end of the strand toward the rotating bale; a bale sensor for sensing a bale parameter which increases as the rotating bale is being formed so as to reach a desired value when the rotating bale is fully formed; a controller responsive to the bale sensor for controlling a bale wrapping cycle during which the controller controls the twine dispensing arm to move from the home position to the twine insert position, the controller being responsive to the bale sensor for controlling the twine pusher to push the dangling end of the strand toward the rotating bale; and, a twine motion sensor for sensing motion of the strand when the dangling end is caught up in the rotating bale; the controller being responsive to the twine motion sensor when the dangling end is not caught up in the rotating bale to automatically abort the bale wrapping cycle and initiate a new bale wrapping cycle. In a preferred embodiment, two twine dispensing arms are provided for dispensing two twine strands.
The controller aborts the bale wrapping cycle by returning the twine dispensing arm(s) to the home position and returning the twine pusher to the first position to cut the strand(s), the controller initiating the new bale wrapping cycle by again moving the twine dispensing arm(s) to the insert position and moving the pusher to the second position.
Yet another object of the invention is to provide a bale wrapping system as described above and further comprising an audible alarm, the controller energizing the audible alarm when N consecutive new bale wrap cycles are aborted because the dangling end(s) of the strand(s) is/are not caught up in the bale, N being an integer greater than zero.
According to one aspect of the invention, a wrap cycle is automatically initiated when a full bale has been formed. It is not necessary for the operator to press a wrap key to initiate a wrapping cycle.